1. Field of the Invention
The present invention relates to an air blower in which a motor rotatably drives a fan.
2. Description of the Related Art
Conventionally, the motor rotating shaft of an air blower of this type is composed of a part whose sectional view is D-shaped and a circular bar, and the D-shaped part is inserted into a resin fan. The gap between the D-shaped part and the circular bar prevents the fan from moving toward the motor and, therefore, contact between the fan, which is a rotary body, and a motor housing, which is a non-rotary body, can be avoided.
Moreover, in the above-mentioned conventional air blower, the machining cost of the rotating shaft is high because the D-shaped part is formed in the rotating shaft. Contrary to this, an air blower is widely known, in which the D-shaped part is not used, a rotating shaft whose shape is circular and solid on the whole is used, and a resin fan is press-fitted onto the rotating shaft.
However, in the latter conventional air blower, there is no gap corresponding to the gap in the former conventional air blower, therefore, if the joining force between the fan and the rotating shaft is decreased due to the time degradation and high-temperature creep of the resin fan, etc., it is likely that the fan will move toward the motor and come into contact with the motor housing.
As described above, if the fan comes into contact with the motor housing, a problem occurs that the motor housing, which is a non-rotary body, prevents the fan from rotating and the fan cannot supply air.